Although not illustrated, a conventional permanent magnet molding apparatus is generally so constructed as to fill powder of magnet molding material into a cavity of a metal die unit including a die, in which the cavity is formed, and a punch located against the die and to pressurize the powder of the magnet molding material with the punch while magnetizing the powder by applying a magnetic field to the powder by means of a pair of coils situated in a surrounding area of the metal die unit, as disclosed in Japanese Laid-open Patent Publication No. H7-115030,for example.
In the conventional permanent magnet molding apparatus constructed as described above, a molded permanent magnet product is taken out of the metal die unit when finished and the powder of the magnet molding material is filled in the emptied cavity. Since permanent magnet products are produced one after another by repeating such product removal and powder filling cycles in successive turns, it is necessary to interrupt magnetizing and pressurizing operations while the powder of the magnet molding material is being filled, causing a deterioration in productivity. In addition, since the powder of the magnet molding material is filled in an area where the magnetic field is applied, there have been a problem that there occur variations in the amount of the filled powder of the magnet molding material, resulting in a reduction in reliability.
This invention has been made to solve the aforementioned problem and, accordingly, it is an object of the invention to provide a permanent magnet molding apparatus capable of achieving an improvement in productivity and reliability.